ezPDF does, too.. it is able to directly take files from Dropbox, Google Docs and from a direct web connection!!
It also reads epub, naturally (I'm saying that 'cause the name seems to suggest a simple PDF reader)..

EDIT:
actually my biggest problem is that I'm not able to use my Nexus directly with Calibre on Linux..
I tried to plug it on Win7 and Calibre recognizes it as usually; Using Slackware Linux Calibre works normally with my smartphone, for example.. but not with Nexus 7.. I suppose it is related to mtp file system used by Nexus.. but.. I don't know what to do..

reading this thread now I'm setting up things like that: I connect a folder as virtual Android device with Calibre; then I'll put a simlink to this folder into Dropbox folder; then from Nexus 7 I'll connect to dropbox someway (ezPDF opr dropsync or other) and download epub files..

actually my biggest problem is that I'm not able to use my Nexus directly with Calibre on Linux..

I use Calibre Companion (CC) Android App to connect my Nexus 7 as a device to calibre. This is a great tool for managing books on your device. I no longer import books into any reader app. I simply open the books directly from CC into the reader app of my choice.

That probably is easier, but I won't put anything of mine in the so called cloud. Not Dropbox, Googles, Amazons or anyone elses storage space. portable disks are cheap now a days and getting bigger and cheaper. There is no need to put any of your property in someones elses control to risk losing it.

Well, back to my orig question. I have these lovely resizeable icons on my nexus 7 start page called My Library-all of which mean nothing to me... I have now somehow gotten rid of that whole thing--- does anyone have any idea how to add content I AM interested in to that My Library interface or make your own customized start page? Thanks. I have no problem getting books on my nexus-- I already have hundreds but am not buying thru Google store so can't make the covers show up in My Library start pg. Thank you for your help.

Well, back to my orig question. I have these lovely resizeable icons on my nexus 7 start page called My Library-all of which mean nothing to me... I have now somehow gotten rid of that whole thing--- does anyone have any idea how to add content I AM interested in to that My Library interface or make your own customized start page? Thanks. I have no problem getting books on my nexus-- I already have hundreds but am not buying thru Google store so can't make the covers show up in My Library start pg. Thank you for your help.

I think the Google "My Library" widget only shows content purchased through the Play store.

Some reading apps have widgets. Haven't tried it myself but Aldiko's might do what you want.

Well, back to my orig question. I have these lovely resizeable icons on my nexus 7 start page called My Library-all of which mean nothing to me... I have now somehow gotten rid of that whole thing--- does anyone have any idea how to add content I AM interested in to that My Library interface or make your own customized start page? Thanks. I have no problem getting books on my nexus-- I already have hundreds but am not buying thru Google store so can't make the covers show up in My Library start pg. Thank you for your help.

Sorry if I am "dumbing down" this explanation too much, but I want to answer your question thoroughly and am not able to tell how much of the following you may already know. Also, my knowledge of the Nexus 7 & Android reading apps is far from complete, so others should feel free to offer corrections and/or additions.

It sounds like the "My Library" screen you liked so much was the widget for Google Play that is by default displayed on your opening screen when you first start up the Nexus. You can find it when you go to your apps/widgets library (accessed with the button that looks like a circle with 6 squares) and look under the widgets section. Iif you still have Google Play installed, it will be listed under Play - My Library. And just for the record, I also think it's a spiffy-looking widget.

To get a widget onto your display screen, just tap and *hold* the widget and you should be taken to your display screen, where you can then release it to drop it where you'd like on the screen. You can then resize and adjust it as you deem fit.

However, this widget will *only* display books your are reading through the Google Books app. AND, unfortunately, that reader app will not currently allow you to load/read books that you did not acquire from Google Play. Judging from the Books known issue page, it does not look like Google has any plans to change this anytime in the near future.

So what I think you will want to do is look for is a reader app that has an associated widget that is somewhat similar - and that you will like reading with, of course. I can tell you right now that neither the Kindle or Nook apps have such a widget.

You might try researching some of the other reader apps available (Aldiko, Moon+, CoolReader, etc.) and see if any of them have a widget to your liking. Even if they don't, they should still allow you to import and read all your non-Google purchased .epubs! Note that some apps may require you to purchase a higher-priced version in order to get a particularly useful widget with it.

Yes I already knew CC, but I can't always use it'cause often I don't have a internet connection!

For the record Calibre Companion (CC) does not require a internet connection to use the app. It does require wifi in your home to initially load books onto your device. CC connects to calibre locally as a device via wifi in the same manner that other ereaders connect to calibre locally as a device via a USB cable. Once the books are loaded on your tablet wifi is no longer needed and at that point CC can be used to organize, search, sort and launch your books in the reading app of your choice.

i create my own cloud service by using a software called pogoplug pc (one time purchase of about $30). once you have this installed, you can designate any folder/drive (internal or external) accessible via the net. pogoplug also sells hardware devices that serves the same purpose. so the "cloud" here is actually your own drive at home. the company has free apps for ios as well as android that you can use to access your files. with this app on your tablet, just navigate to the ebook you want that sits on your very own "cloud" and use the "open in/open with" feature to point to coolreader/aldiko/whatever you use to read.

On the Google Play store is an app called "Nexus Media Importer". Get an OTG (on the go) USB cable, put video or book files on a USB flash drive - and suddenly you can just plug in a flash drive into the cable and watch movies, play music or ... copy epub and other files from the flash drive to the internal storage.

When my Nexus 7 OS upgraded, the app stopped working. So I used my gmail account to upload files to Drive, then downloaded the files into a Books folder from the gmail app on the Nexus 7.

The Nexus Media Importer recently updated so I suspect the author fixed the problem. But I have about 200 books I need to get through before I need to re-load.

Thanks ginnjnsn - you've got what I'm talking about -- I think the Google Play My Library widget looks spiffy too, and I'd love to utilize it but haven't (and may not, who knows) buy anything from the Google Store, so what a waste - boo. WAS wondering if anyone knew of a similar looking widget where I could put my OWN content I am currently using/interested in and have it look like that and be accessible as soon as I open my Nexus 7 -- I too already have hundreds of books that were not bought on Google Play - I know how to add them to the Nexus no problem, that's not my issue. My issue is just the aesthetics of the My Library widget and if I could utilize it to my own devices! : )

I am currently using Moon Reader, have found it to be excellent and not glitchy at all, and very customizable, which I like. Like Aldiko for a while but it started freezing -- coincidentally or not, around the time I downloaded and checked out Kobo, which wasn't that great for me.

Maybe I'm a control freak - I like things the way I want them and there's no satisfying me otherwise! LOL! I figure if I pay the big bucks for a tool, I should be able to have it work however I deem. :P